Reversible mechanism



Dec. 4, 1956 H. ,N. Ross REVERSIBLE MECHANISM 2 Sheets-Sheet J Filed OCT.. 12, 1954 .s mw MR Y E. WMI/m. w H m e r u r HW A y/ B :IIL im?. i

Dec. 4, 1956 H. N. ROSS REVERSIBLE MECHANISM 2 Sheets-Sheet 2 Filed OCT.. 12,' 1954 INVENToR. HUGH N. Ross United States pm:ent

- RnvERsmLu MnonANrsM Hugh Neil Ross, Montgomery County, Md., assiguor to YAmerican Instrument Company, lne., Silver Spring, Md.

Application October 12, 1954,-Serial No. 461,760

15 Ciaims. (ci. :f4- 312) This invention relates .to reversible mechanisms, and

"more particularlyk to 'a mechanism for positively transmitting unidirectional movement to ,a driven member when an associated drive member moves either in a forward or a reverse direction from a reference position thereof..

A main object ot the invention is to provide a novel .and improved reversible drive mechanism arranged to provide positive drive in a fixed directionre'sponsiveto the excursion of lthe input force or torque'in either direction rfrom 1 a reference condition.

fA'further object of vthe invention is to provide a novel and improved reversible drive mechanism forproviding 'positive vdrive in a given direction in response to the applicati-on vot' linput force or torque in either of two directions from a reference position, said mechanism being provided with'means indicating the relative direction ofthe applied input force vortorque.

Asti-ll further object of the invention is to provide an improved reversible drive mechanism suitable Vfor use with a condition-responsive device rto tnansrnit positive unidirectional torque or force to'an indicator or to ase't of printing Wheels.

A still'funther object of the invention is to provide an Y'improved 'reversible Vdrive 'mechanism for transmitting positive unidirectional force lor torque, said-mechanism being simple in construction, providing an indication: of the'direction of excursion ofthe input "element thereof fromua reference. position, vand 'being especially suitable for Ause in transmitting indications from la conditionresponsive device, lsuch as a temperatureLresponsive mechanism, a humidity-responsive mechanism, or the-like, to'a unidirectional indicating means, suchsas. afregister `device .oft-he type having indicatingV or printingf'wheels provided lwith numerical indicia' ofy positive value:

Further objects :and advantages of the invention *will become apparent from the following ldescription: and claims,-and from the accompanying' drawings,4 wherein:

Figure l is a top plan View, partly in'horizontal crosssection, of a reversibile drive mechanism constructedl in accordance withfthe present invention.

. Figure 2 isa cross-sectional view takenon line Figure 1.

Figure' 3 'is across-sectional View takenon Line6-'i3 ofFigure 1.

.Figure-4 Iis a rear'elevational View of themechanism ofFigure l.

vFigure 5 is "an enlarged cross-sectional detail View taken on line V5-5 of Figure 1.

Figure 6 is'an enlarged side elevational detail `view 'of one of the drive Washers employed in the mechanismof Figures 1 to 5.

YFigure 7 is an elevational `detail View taken on `line 7--7 of "Figure 6.

.Figure' 8 :is an 'enlarged elevational detailiview taken on line 18=8 .of "Figure 1.

R'efer-ring to :the drawings, 1l generally designates a reversible drive/mechanism accordingl to thefpresent in-v `means for indicatingl negative values. of-temperature'variations, the mechanism 13 would .ordivention, which may be employed, forfexampleybetween an input device`12 and an indicating or registering device 13.

vThe inputdevice 12 may be any conventional conditionresponsivedevice having an output shaft which rotatesy in accordance with variations inthe condition to which it responds, for example, a temperature-responsive recorder mechanism orf the self-balancing type having va rselfbalancing ypotentiometer means and employing a Wheatstone bridge circuit, thismechanism being well'k/nown in 'the art. Alternatively, the device .12 may be a humidity-responsive mechanism, or may even be amanually operated device which has an output shaftor similar member which maybe rotated in either one direction orthe other, and wherein it is desirable to record orindicate theexcursions in both directions of the output mornber from a designated reference value or position of the output shaft.

The indicating or registering `device 13 is also conventional and is of the type providing a positive indicated value with respect to a base or reference value, for exam- 'having indicating or printing 'vv-heels which can exhibit onlypofsitive-va'lue indications and whichhas no inherent Thus, inthe case n-aily be suitable for providing indications of values above fzero, or above such other reference value as may be selected. v

The mechanism ll. comprises a hatse'pflate y14 on which are suitably mounted the spaced opstanding hearing brackets'lS andl in which is journalled the'longitudinal shaft-17, said shaft being coupled directly toA the vinput shatit olf the indicating or registering device 13. Spiral Ispringsfl, 18 surround the shaft 17 and are connected between Vshaft 17 and 'base plate 14, biasing-shaft V17 ltowards a nonmal position correspond-ing to thezero,"or

otherreference starting position, olf the input shaft of the indicating or registering device'l Thus, shaft'l? can oh-lyberotated to positions spaced 'singularly in one Vdirection from said zero or starting position ot theshatt. Designated at@ is the input shaft of .the dev-ice- 11, said shaft'19' being journalled transverse tothe sh-aift 17 on' an opstanding bearing bracket Ztl mounted onhase'platef 14. .Theoutputfshaft ofthe input devicelZ is' connected directly to the input shaft 19.

*Securedr to y.the input shaft 19 -is a bevel vgeary 2l which mesheswithiapair 'of opposing similar bevelr gears22arid 23: secured on'respectivesleeve members '24 andfZSrota-tably-mountedfon the. intenmediate iportion ot Ish-att `17 .on opposite sides of a spacer'. sleeve '26 secured onI said `shaft-l'has shown,as by a set screw '27. Clamped'on v similar outwardly projecting drive arml.

Loosely mountedon shaft l7 betweenbevel'gearZS and drive collar-28 are a plurality of washers132, vsaidiwashers each being formed with an outwardly projecting'hooke'd lug Y33, the lugs'33 projecting -in the same'direction; namely toward the drive collar 28,' as shownin Figure l. "Secured to the bevel gear 23 is drive pin {i4-which is. drivingly engageable With the lug-33 of the adjacent Washer '32, whereby the gear may transmit torque in-a counterclockwise direction, as viewed from the right vendof fthe device inFigure l, to the adjacent washer 32. The `lugs 33 are of such yWidth that they will vsuccessively'--e-njgage eachother, and the lug 33 'on the rightl end washer-32 Williengage thefarm 30 of collar :28, forspositively. trans-` mitting such counterclockwise torque when the input shaft 19 is in the reference position thereof, for example, in its zero position. Thus, when the input device 12 applies a clockwise torque to shaft 19, as viewed from the front of the device 11 in Figure 1, bevel gear 21 will rotate, and will cause bevel gear 23 and driving pin 34 to transmit driving torque through the interengaging lugs 33 to the drive arm 30, to cause shaft 17 to rotate counterclockwise, as viewed from the right side of the device in Figure l. This rotation of shaft 17 will produce a positive indication or setting of the changeable element or elements of the device 13. When the aforesaid clockwise, or positive input torque on the shaft 19 is removed or relaxed, the springs 18 return the shaft 17 toward its Zero or reference position.

Loosely mounted on shaft 17 between bevel gear 22 and drive collar 29 are a plurality of Washers 32', similar to washers 32, and having hooked lugs 33 directed toward drive collar 29. Secured on bevel gear 22 is a drive pin 34' which is engageable with the lug 33' of the adjacent washer 32'. The lug 33 on the washer 32 adjacent collar 29 is engageable with the drive arm 31 to transmit counterclockwise driving torque thereto, as viewed from the right end of the device in Figure 1. Thus, the lugs 32 are of such width that when they are interlocked, and the lug 33 adjacent the collar 29 engages arm 31, the pin 34 will be in driving engagement with the lug 33' of the washer adjacent bevel gear 22 when the shaft 19 is in its reference or zero position. When shaft 19 rotates in its negative, or counterclockwise, direction from its aforesaid reference or zero position, as viewed from the front of the device in Figure 1, bevel gear 22 is rotated counterclockwise, as viewed from the right end of the device, and transmits counterclockwise driving torque to shaft 17 through pin 34', lugs 33', and arm 31. This again causes shaft 17 t0 provide a positive indication or setting of the changeable element or elements of the device 13.

In order to indicate whether the input device 12 is operating above or below its reference or zero condition, a range indicating wheel 35 is provided. Wheel 35 is journalled on a horizontal shaft 36 supported on suitable brackets 37, 37 mounted on base plate 14. An apertured viewing plate 38 is secured to plate 14, the aperture 39 of plate 38 providing a view of the periphery of wheel 35 adjacent thereto, as shown in Figure 8. Said periphery is provided with suitable spaced indication marks or embossments, such as plus and minus signs to respectively signify the ranges above and below the reference or zero position of shaft 19.

Iournalled between suitable supports 40, 40 is a horizontal shaft 41 on which is mounted a gear 42 meshing with a gear 43 on shaft 19. Also mounted on shaft 41 is a cam 44 having a notched portion 45 of reduced radius. Designated at 46 is a lever pivotally mounted at its intermediate portion on an upstanding support 47 secured to plate 14. One end portion of lever 46 has a depending follower lug 48 engaging the periphery of cam 44. The other end portion of lever 46 is formed with a slot 49 slidably engaging a laterally projecting pin 50 carried by wheel 35. A coiled spring 51 connects lever 46 to base plate 14, said spring being located between follower lug 48 and the pivotal connection of lever 46 to support 47, as shown in Figure 2, to bias the follower lug 48 against the periphery of the cam.

When follower lug 48 is in the position shown in Figure 2, namely, is at the clockwise end of notch 45, wheel 35 provides a normal or plus indication through the viewing aperture 39 of plate 38. When cam 44 is rotated counterclockwise from its position of Figure 2, follower lug 48 is forced onto the larger radius portion 52 of cam 44, causing lever 46 to rotate clockwise, thus causing wheel 35 to rotate counterclockwise, moving the negative indication into view through the aperture 39. This occurs when shaft 19 rotates counterclockwise, as

viewed from the front of the device in Figure 1, through its reference or zero position, since the rotation of shaft 19 is transmitted to cam 44 by the meshing gears 43 and 42.

From the above, it will be apparent that regardless of the direction of rotation of input shaft 19 (within the design range of the device), the shaft 17 can be positively driven in only one direction by the bevel gears 22 and 23, for example, in a counterclockwise direction, as viewed from the right side of the device in Figure l. The springs 18 merely act to urge the shaft 17 toward its zero or reference position. When one of the bevel gears is driving, the other bevel gear is inoperative, since the lugs of its associated washers are not in driving interengagement and said washers are in a floating condition on the shaft 17.

The range-indicating wheel 35 may obviously be a printing wheel and may be employed to record the positive or negative nature of the position of input shaft 19 simultaneously with the numerical record provided by the printing wheels of the device 13.

When the input shaft 19 returns to its zero position, the output shaft 17, under the biasing force of the springs 18, also returns to zero position, at which time the positive drive lugs 33 are ready to unlock. The negative drive lugs 33 are now ready to lock and to drive the output shaft 17 in the same direction away from the zero position as said output shaft was driven by the positive drive lugs (giving the same type of indication on the device 13 for values below zero as for values above zero).

The auxiliary wheel 3S registers the passage of the input shaft 19 through zero by the action of the cam 44, whereby wheel 35 and device 13 together provide an absolute indication of the position of input shaft 19.

The above described device may be employed in any recording or indicating device Where the range includes zero, such as a device for measuring temperature, relative pressure, or the like, or for measuring deviations from an arbitrary reference value, as in length gauges, or in frequency-measuring devices where the frequency depends on the position of a tuning shaft, or the like.

The input shaft 19 may be operated by any condition-responsive device which covers a range wherein zero is in the intermediate portion of the range.

The mechanism is applicable to any system having a self-balancing type of responsive mechanism, as for example, self-balancing bridge devices wherein the responsive element rotates in accordance with variations in the condition being measured.

While a specific embodiment of a reversible drive mechanism has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. In a mechanism of the character described, an input element having a unique reference position and being movable in opposite directions through said reference position, an output element, means coupling said input element to said output element and arranged to drive said output element in one direction only, regardless of the direction of movement of said input element, and means operating in response to the passage of said input element through said reference position indicating the direction of excursion of said input element from said unique reference position thereof.

2. In a mechanism of the character described, an input element having a unique reference position and being movable in opposite directions through said reference position, an output element, means coupling said input element to said output element and arranged to drive said output element in one direction only, regardless of the direction of movement of said input element, and indicating means operated in response to the movement of said input element through said unique reference position thereof.

3. In a mechanism of the character described, an input element, an output element, means coupling said input element to said output element and arranged to drive said output element in one direction only, regardless of the direction of movement of said input element, indicating means operated in response to the movement of said input element through a predetermined reference positionl thereof, and means biasing said output element toward a position corresponding to said predetermined reference position of said input element.

4. in a mechanism of the character described, an `input shaft having a unique reference position and being movable in opposite directions through said reference position, an output shaft, means coupling said input shaft to said output shaft and arranged to drive said output shaft in one direction of rotation only, regardless of the direction of rotation of said input shaft, and indicating means operated in response to the movement of said input shaft through said unique reference position thereof.

5. In a mechanism of the character described, an input shaft, an output shaft, means coupling said input shaft to said output shaft and arranged to drive said output shaft in one direction of rotation only, regardless of the direction of rotation of said input shaft, indicating means operated in response to the rotation ofl said input shaft through a predetermined reference position'thereof, and means biasing said output shaft toward a position corresponding to said reference position of the input shaft.

6. In a mechanism of the character described, an input shaft, a first gear drivingly connected to said input shaft, an output shaft, respective second and third gears rotatably mounted on said output shaft and meshing with said first gear, means drivingly coupling said second gear to said output shaft responsive to the rotation of said input shaft in one direction beyond a predetermined reference position thereof, and means drivingly coupling said third gear to said output shaft responsive to the rotation of said input shaft in the opposite direction beyond said reference position.

7. In a mechanism of the character described, an input shaft, a first gear drivingly connected to said input shaft, an output shaft, respective second and third gears, means rotatably supporting said second and third gears in meshing engagement with said first gear, means drivingly coupling said second gear to said output shaft responsive to the rotation of said input shaft in one direction beyond a predetermined reference position thereof, and means drivingly coupling said third gear to said output shaft responsive to the rotation of said input shaft in the opposite direction beyond said reference position.

8. The structure of claim 7, and wherein said coupling means is arranged to transmit driving torque to the out'- put shaft in one direction only, regardless of the direction of rotation of the input shaft.

9. The structure of claim 7, and means indicating the direction of rotation of said input shaft from said predetermined reference position.

10. The structure of claim 7, and indicating means operated in response to the rotation of said input shaft through said reference position.

11. In a mechanism of the character described, an input shaft, a tirst gear drivingly mounted on said input shaft, an output shaft arranged at right angles to said input shaft, respective second and third gears rotatably mounted on said output shaft and meshing with opposite portions of said first gear, whereby said second and third gears are rotated in opposite directions by said input shaft, respective drive members secured to said output shaft and spaced respectively from said second and third gears, and driving means mounted on the output shaft between the second and third gears and the respective drive members, said driving means being arranged to drivingly couple the second gear to one of said drive members when the input shaft rotates in one direction beyond a reference position thereof and to drivingly couple the third gear to the other drive member when the input shaft rotates in the opposite direction beyond said reference position, whereby the output shaft can be driven in only one direction by said input shaft.

12. The structure of claim 11, and indicating means ,operated in response to the rotation of said input shaft through said reference position.

13. The structure of claim 11, and means biasing the output shaft toward a predetermined reference position.

14. The structure of claim 11, and wherein said driving means comprises respective groups of washers rotatably mounted adjacent to each other on the output shaft, said washers each having a lug projecting toward the associated drive member, said lugs being interengageable with each other and with the associated drive member, and respective projections on the second and third gears engageable with the lugs of the adjacent washers.

15. The structure of claim 14, and means biasing the output shaft toward a position wherein the lugs on the washers of both groups are substantially interlocked and are substantially in driving relation to the respective drive members and the projections on the second and third gears are substantially in driving engagement with the lugs of said adjacent washers.

References Cited in the le of this patent UNITED STATES PATENTS 1,736,064 Walker NOV. 19, 1929 

